The invention described herein may be manufactured and used by or for the Government of the United States of America for Governmental purposes without the payment of any royalties thereon or therefor.
(1) Field of Invention
The present invention relates to an elastomeric launch assembly for expelling a device from a vehicle, and more particularly to an elastomeric launch assembly which is operationally insensitive to ambient pressure and which can launch the device, such as a counter measure, defensive weapon, or an offensive weapon with variable energy.
(2) Description of the Prior Art
It is well known that submarines must be capable of delivering countermeasures, defensive weapons, offensive weapons, and other devices from externally stowed modules or tubes, in order to defend themselves against attacking torpedoes and other threats. Conventional launch assemblies utilize chemical gas generators in order to force the devices from their launch tubes. Because conventional launch assemblies rely upon pressure developed at the base of the devices inside of the launch tubes, they are sensitive to ambient pressure. At depths of greater than about several hundred feet the ambient pressure can often prevent the launched devices from achieving acceptable launch velocities.
In addition to being sensitive to ambient pressures, current gas generator based systems are not operated over a range of energy levels. Instead, these generators are ignited and burn at a predetermined rate, thus forcing the device from its launch tube at a fixed velocity. When stealth operation is a priority, conventional launch assemblies cannot be adjusted to provide a low impulse, or xe2x80x9cquietxe2x80x9d launch.
Another issue associated with conventional launch assemblies is that the handling of their combustible or explosive gas generators represents a significant cost. To safely handle the combustible or explosive gas generators requires an investment in time, money and training.
Accordingly, there is needed in the art a launch assembly which is capable of performing at various ambient pressures, which preferably can be operated in a range of launch energy modes, and which is safe and reliable during operation.
The present invention is directed to a launch assembly having an elastomeric tube designed to at least partially receive the body of the device to be launched. Before launch, the tube is secured to a support housing having an inboard end and an outboard end. To launch the device, an outboard end of the elastomeric tube is movable outwardly along the length of the housing by an extending device. In one embodiment, the extending device includes a ring attached to both the outboard end of the tube and to at least a pair of rails which run along the length of the housing, from the inboard end to the outboard end. The rails may preferably be threaded, and the ring may be attached thereto by nuts and linear bearings, which are preferably disposed around the periphery of the ring and matingly engage the threaded rails in one embodiment. A motor may be provided to turn the screws which, when turned, operate to force the nuts attached to the outboard end of the ring to move the ring toward the outboard end of the support housing.
As the attached ring and outboard end of the elastomeric tube moves, the inboard end of the tube is restrained by a release mechanism and remains stationary. Thus, as the outboard end moves outwardly and the inboard end remains stationary, the elastomeric tube becomes elongated. The tube may be elongated a predetermined amount, at which time the inboard end of the elastomeric tube is released from the base assembly by the release mechanism. In one embodiment, the release mechanism includes a hook releasably engaged with a plate supported on the inboard end of the tube. To release the inboard end of the tube, the hook is rotated from engagement with the plate. Releasing the inboard end allows it to travel toward the now stationary outboard end with a sufficient velocity to launch the device housed within the tube. As will be appreciated, the amount of elongation of the tube is related to the amount of possible launch energy. Thus, greater elongation of the tube provides a greater launch velocity, while shorter elongation provides a reduced launch velocity, as desired.